The present invention relates to a scanner with a built-in microcontroller to decrease the delay of transmission.
A scanner has become a very popular peripheral equipment of the computer. Generally, a scanner is connected with a personal computer (PC) by using a printer port or an interface card now. Please refer to FIG. 1 which is a conventional scanner 11 connected with the PC 13 by the printer port 12. FIG. 2 is a flowchart showing a scanning process of the scanner 11 connected with the PC 13 through the printer port 12. When the PC 13 sends a scanning required signal for starting the scanner 11, a scanning process will be carried out. During the scanning process, the PC 13 is continuously detecting whether the scanner 11 is ready to scan the second image line after the first image line has been scanned. If the scanner 11 is not ready, the PC 13 will keep detecting until the scanner 11 is ready for scanning the next image line and sending out the scanning data to the PC 13.
Currently, various kinds of peripheral equipment of the computer are getting more and more, e.g. mouse, joystick, printer, and monitor, all of which have become indispensable and have their own interfaces. Therefore, the universal serial bus (USB) is developed for solving the problems of connection and usage. The USB is adapted to connect all kinds of peripheral equipment which is in conformity with the USB standards. Of course, the scanner can also be connected with the computer through the USB. Please refer to FIG. 3 which is a block diagram of the conventional scanner 31 which is in conformity with USB standards and is connected with the PC 33 by the USB 32. FIG. 4 is a timing diagram of the signal transmission of the scanner 31 connected with the PC 33 through the USB 32. Basically, the transmission way of the USB is to send all received signals at the time point of every frame. As shown in FIG. 4, the length of each frame is 10xe2x88x923s. When the PC 33 generates a scanning required signal at the time point A, however, the USB 32 does not send the scanning required signal to the scanner 31 immediately, but send it with other signals generated by other peripheral equipment, connected with the USB 32 in series, at time point of frame 1. However, depending on the priority of signals, the scanning required signal sometimes is delayed to be sent at the time point of the frame 2. If the scanner 31 is ready to scan a first line segment until the time point B, the response signal of the scanner 31 to the PC 33 through the USB 32 will be delayed to be sent at the time point of the frame 3. Then, the command signal of the scanner 31 for scanning a next image line and sending back the scanning data from the scanner 31 to the PC 33 will be delayed to be sent at the time point of the frame 4.
Because of the characteristic of the USB 32, the signal transmission will be delayed (as shown in FIG. 4). It brings about an increase in the scanning time and influences the efficiency. The main purpose of the present invention is to develop a more efficient scanner by using a built-in microcontroller to improve the drawbacks as discussed above.
An object of the present invention is to provide a scanner with a built-in microcontroller to decrease the delay of transmission. The scanner includes: an image-picking device for picking digital data of a plurality of image lines, a microcontroller electrically connected to the image-picking device for continuously detecting whether the image-picking device is ready to scan a second image line after a first image line is picked and send out digital data which have been picked, and an interface device of a USB electrically connected to the image-picking device and a universal serial bus (USB) for receiving the digital data sent out by the image-picking device and transmitting the digital data to a data processing device through the USB for further processes.
In accordance with one aspect of the present invention, the image-picking device is a charge-coupled device (CCD).
In accordance with another aspect of the present invention, the data processing device is a personal computer (PC).
The present invention may best be understood through the following description with reference to the accompanying drawings, in which: